Title
Evaluating Stochastic Rankings with Expected Exposure
Abstract
We introduce the concept of expected exposure as the average attention ranked items receive from users over repeated samples of the same query. Furthermore, we advocate for the adoption of the principle of equal expected exposure: given a fixed information need, no item should receive more or less expected exposure than any other item of the same relevance grade. We argue that this principle is desirable for many retrieval objectives and scenarios, including topical diversity and fair ranking. %Leveraging user models from existing retrieval metrics, we propose a general evaluation methodology based on expected exposure and draw connections to related metrics in information retrieval evaluation. Importantly, this methodology relaxes classic information retrieval assumptions, allowing a system, in response to a query, to produce a distribution over rankings instead of a single fixed ranking. We study the behavior of the expected exposure metric and stochastic rankers across a variety of information access conditions, including ad hoc retrieval and recommendation. %We believe that measuring and optimizing expected exposure metrics using randomization opens a new area for retrieval algorithm development and progress.
Year
DOI
Venue
2020
10.1145/3340531.3411962
CIKM '20: The 29th ACM International Conference on Information and Knowledge Management Virtual Event Ireland October, 2020
DocType
ISBN
Citations 
Conference
978-1-4503-6859-9
14
PageRank 
References 
Authors
0.59
31
5
Name
Order
Citations
PageRank
Fernando Díaz1366.60
Bhaskar Mitra244126.26
Michael D. Ekstrand345635.67
Biega Asia J.4141.26
Ben Carterette5215.08